This invention relates to articles that have the capability to control or transport fluids, especially biological fluids. In one embodiment this invention relates to medical wound dressings and drains and intravenous access site
The control and/or transport of biological fluids poses many problems at different stages in treatment or diagnosis processes. During surgery, steps are undertaken in an effort to control and/or transport the fluids which result from the surgery. In some instances these fluids are needed to be recycled back to the patient. For example, vital blood lost from the patient may be returned in emergency situations. In other instances fluids are needed to be controlled so that an aseptic and safe operating room environment is maintained. It is often times desired, for example, to avoid spillage of fluids onto the operating room floor where it would create an unsafe situation and mess. After surgery, the need to control and/or transport fluids remains. For example, wound exudate can pose problems in the treatment and care of the wound site and needs to be handled. Also, the delivery of fluid medicaments to a wound site can present challenges.
Several surgical drapes and pouches have been designed in an attempt to control fluids generated during surgery. Many of these devices utilize absorbent padding or plastic pouches to collect the fluid. In many situations, however, there does not exist enough room at the site where the fluid is emanating from to adequately control the fluid.
Suction tubes, optionally connected to a central vacuum line or remote vacuum source, may also be employed to collect fluids from a wound site. These tubes have a significant number of limitations which inhibit the desired management of the fluid. For example, post operative wound drain tubes create significant patient discomfort and can be a source of infection. Furthermore, many wounds require multiple drain tubes.
In the treatment of many wounds it is beneficial to keep the wound moist while removing excess exudate. This environment provides an optimum wound healing environment, reduces pain, and provides an environment for autolytic debridement and re-epilethlialization. Excess fluid, however, can lead to problems such as maceration (skin breakdown) and microbial infection of the wound site. For this reason, many wound dressings are sometimes designed to have absorbent pads and/or high moisture vapor transmission rates (hereinafter xe2x80x9cMVTRxe2x80x9d), i.e. the excess fluid is allowed to transmit or evaporate through the wound dressing.
Fluid can be a particular problem when dealing with highly exuding wounds, IV sites, as well as sites for gatric (G), jejunostomy (J) and nasal gastric (NG) tubes. For example, many commercially available intravenous access site dressings (hereinafter xe2x80x9cI.V. Dressingsxe2x80x9d) do not have sufficient MVTR to permit rapid evaporation of moisture through the dressing. Consequently, in some instances this can result in fluid pockets forming beneath the dressing around the puncture site. This fluid can result in one or more problems such as xe2x80x9cbandage liftxe2x80x9d (which reduces the ability of the bandage to secure the IV line to the skin), skin maceration, or bacterial infection.
A stated advantage to certain of these dressings is transparency of part or all of the dressing. This allows for direct visual observation of the wound healing progress. For example, thin film adhesive coated dressing having a site revealing xe2x80x9cwindowxe2x80x9d surrounded by an absorbent such as a hydrocolloid have been tried. Unfortunately, however, these dressings require that the xe2x80x9cwindowxe2x80x9d be relatively small to ensure that the fluid be in sufficient direct contact with the absorbent to prevent fluid build up. Even so, these small dressings may not absorb fluid rapidly enough to prevent fluid build up around the IV puncture site.
Alternatively, attempts have been made to place a gauze absorbent or an xe2x80x9cisland dressingxe2x80x9d (i.e., a dressing having an xe2x80x9cislandxe2x80x9d of absorbent fabric or hydrophilic foam contained therein) directly over the wound. Island dressings are able rapidly to absorb fairly high amounts of wound exudate and, therefore, are useful for highly exuding wounds. Unfortunately, however, the presence of the absorbent directly over the wound prevents visual observation of wound healing. Finally, certain transparent hydrocolloid dressings are also available that absorb the fluid into a polymeric matrix. These dressings can absorb large volumes of fluid but generally the absorption is not very rapid and hydrocolloids tend to break down in the wound.
Drug delivery dressings have been developed that contain a reservoir of a suitable medicament. The reservoir is placed in contact with the skin and the medicament is allowed or assisted to permeate the skin. Unfortunately, the amount of drug contained within the dressing is limited for a particular size of dressing and these dressings do not have a capability to be recharged from a remote reservoir. Many of these dressings are not suitable for application over open wounds. For example, many transdermal drug delivery devices rely on the barrier provided by the dermis to regulate drug delivery rate.
Otitis media, inflammation of the middle ear, accounts for more visits to pediatricians than any other illness. Otitis media is generally regarded as a complication of eustachian tube dysfunction. The normal eustachian tube is closed, except during swallowing, when it allows pressure equalization between the middle ear and nasopharynx. When it does not close properly, due to inflammation due to a cold, for example, the eustachian tube can act as a conduit for movement of bacteria into the middle ear from the nose. Gram-positive microorganisms, most prevalently S. pneumoniae and S. pyogenes, constitute the bacterial origin of otitis media. Furthermore, if the eustachian tubes are subsequently blocked so that negative pressure develops inside the middle ear, serum may leave the blood vessels in the middle ear under hydrostatic pressure and accumulate there, a condition known as otitis media with effusion.
Treatment of otitis media involves observation and antibiotic therapy, and for infections that persist, surgical placement of ear tubes. Antibiotic treatment of otitis media involves systemic administration of antibiotics such as amoxicillin. Increasingly, the use of antibiotic therapy for treatment of this disease is coming into question due to knowledge that widespread use of antibiotics allows for selection of resistant strains of bacteria. However, most physicians continue to prescribe antibiotics because it is difficult to predict which patients will get well without treatment and which will proceed to chronic otitis media and potentially fatal sequelae such as meningitis.
Installation of ear tubes is another treatment for otitis media. The tubes are grommets that are placed in the tympanic membrane so that a ventilation hole is maintained for fluid to escape from the middle ear. Occasionally, ear tubes are removed by the surgeon after the infection has cleared. More frequently, the ear tubes fall out of the ear after the infection has resolved. In either case, the tympanic membrane usually (in 60-70% of cases) heals with little or no hearing dysfunction. An unresolved problem with current ear tube designs is that they may fall out before the ear infection has resolved; this occurs in up to 25% of cases, increasing total cost of treating otitis media.
Suction tubes have been used in dentistry to help control and remove fluids from the oral cavity. Generally these tubes are pretty simple devices. Unfortunately, however, the tubes in use suffer from some drawbacks. First, they can be very noisy, causing the patient, dentist and/or assistant to become agitated or annoyed. Second, they generally suck fluid from only one point in the cavity. To remove fluid from other areas the tube must be manually repositioned. Moreover, positioning the tube into small openings or isolating individual teeth or regions is precluded. Additionally, there have been reported cases of cross contamination from patient to patient, caused from a malfunction of the suction pump. Finally, the tube is prone to getting blocked by the tissue.
From the foregoing, it will be appreciated that what is needed in the art are articles having a built in capability to control or transport fluids, especially biological fluids. In the case of surgical drape articles, there is a great need for articles that can control or transport fluids emanating from a surgical site. In the case of medical treatment articles (e.g., wound dressings), there is a great need for dressings that keep the wound area at a preferred moisture level, articles that are capable of transporting fluid between the wound site and a remote area, or are capable of delivering a medicament to a wound site. It would be a further advancement in the art to provide such articles in a reliable and low cost manner. Such articles and methods for preparing the same are disclosed and claimed herein.
The present invention provides fluid control or transport articles comprising at least one fluid control film component which comprises a sheet having at least one microstructure-bearing surface with one or more channels therein that permits, promotes, or facilitates control or directional flow of a liquid. Medical treatment articles containing a fluid control film component are provided.
In one embodiment, this invention relates to novel surgical drapes that incorporate a fluid control film. The fluid control film may be incorporated to transport a fluid to a remote site (e.g., facilitate wicking of a fluid away from an operating site and out of the way of the surgeon), deliver a fluid to a site (e.g., facilitate delivery of a medicament or flushing solution to a surgery site), or absorb or contain excess wound exudate.
In another embodiment, this invention relates to novel wound dressings that incorporate at least one fluid control film. The fluid control film may be incorporated to transport a fluid to a remote site, deliver a fluid to a site, disperse the fluid over an increased surface area to promote more rapid evaporation (e.g., through a high MVTR film), or absorb excess wound exudate. The dressings may be fabricated to accommodate wounds of all types, including: burns, abrasions, surgical wounds, lacerations, etc.
The topical wound dressing of one preferred embodiment transports (e.g., wicks) fluid off wounds by capillary action to a remote storage reservoir. This embodiment functions in an opposite manner to conventional wound dressings that place an absorbent over the wound itself. Dressings of this embodiment are preferably able to provide one or more of the following benefits:
1) wound moisture level optionally may be adjusted by modification of the surface topography and/or surface energy of the fluid wick in combination with the MVTR of the dressing;
2) the dressing is optionally and preferably transparent and allows visual inspection of the wound site; and
3) an optional absorbent may be isolated or positioned remote from the wound site, thereby absorbing excess exudate while allowing direct visualization of the wound. The absorbent is preferably covered with a permeable film, thus enabling the healthy tissue surrounding the wound not to be in contact with excess wound exudate.
The fluid transportation or xe2x80x9cwickingxe2x80x9d property may be provided by fluid control film incorporating a microreplicated pattern. The pattern may be provided in the backing or adhesive layer of a dressing, or by a separate piece of film. The storage reservoir is preferably a hydrophilic fabric such as a woven, knit, or non-woven, a hydrocolloid, foam, or a gel system that is able to absorb large amounts of fluid exudate. Preferably a high MVTR transparent or translucent backing is used. Certain dressings may also be used to supply medicaments to the wound such as antimicrobials, antibiotics, growth factors, irrigation fluid, anesthetics/analgesics, and the like. Certain other dressings may incorporate the optional medicaments directly into the adhesive, film backing, or microreplicated fluid transport wick.
In another embodiment, drug delivery dressings are provided. The delivery dressings incorporate fluid control film component to facilitate delivery of a medicament to the skin.
In another embodiment, the present invention provides a novel treatment for otitis media that utilizes novel tympanostomy wicks or tubes and/or a medicament (e.g., an antibacterial agent, preferably one that is covalently attached to the tympanostomy article or placed in the inner ear by means of a syringe through the article itself). The novel wick or tube design utilizes microreplication to produce microchannels that transport fluid, e.g., by capillary action. Preferred designs also incorporate macrochannels to allow drainage of highly viscous fluid that cannot be removed by capillary forces.
In another embodiment, dental suction devices are provided that comprise a fluid control film.